Help required - Circuit for controllable, even heat distribution.

Thread Starter

MRH91

Joined Feb 20, 2022
13
Hello

I'm looking for help with a project I've been wrapping my head around over the past few weeks.

Firstly, I have zero electrical/electronics experience, but I'm only looking for a potential solution to my problem, with which I can take to an electronics engineer, and commission them to manufacture the component for me.

I could take the whole idea to an engineer with the hope they figure out a solution, but I've decided to seek help on this forum too as I'm sure there's many ways that could potentially work.

I require a machine to drill or melt a series of 13 holes in a line (ideally 26 if possible). The holes need to be approximately 3mm in diameter, to be drilled 90mm deep into a foam material, and are spaced on 35mm centres.

I will be manufacturing the framework to hold the system and will create a type of drill press arrangement, which will be attached to the housed components so it can be lowered down into the foam material below.

I've thought about using nichrome or kanthal wire, heated through a circuit system, then lowered into the foam. I've tested a piece of 2.5mm steel heated on a flame, and it melted through the foam perfectly with the hole ending up around 3mm wide. Ideally, this would be the best solution, however the wire would need to be evenly heated throughout the ~100mm total length, and controllable to optimise the best temperature to melt through the foam.

I've thought about using small motors with an attachment to hole a drill bit. I can't imagine this working too well, as the motor housing would have to be 35mm maximum width, in order for the holes to be on 35mm centres and this type of small motor will surely just overheat and not work for long periods of time.

Any ideas on how i'll be able to achieve such a system would be hugely appreciated.

If there's anyone reading this that would be interested in personally working with me on this, please feel free to get in touch and we can discuss pricing.

Thank you!
 

LowQCab

Joined Nov 6, 2012
2,058
There's no need to actually put the Heating-Element into a ~3mm format.
You need a large chunk of metal with 3mm Pins attached to it with the desired spacing,
then heat the large chunk of metal to the appropriate temperature.

A potential problem, regardless of how You accomplish this,
is residue from melted Foam accumulating on the Pins.
This would require routine mechanical cleaning of the Pins,
the requirement for cleaning may vary depending on the type of Foam You will be using.
.
.
.
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
There's no need to actually put the Heating-Element into a ~3mm format.
You need a large chunk of metal with 3mm Pins attached to it with the desired spacing,
then heat the large chunk of metal to the appropriate temperature.

A potential problem, regardless of how You accomplish this,
is residue from melted Foam accumulating on the Pins.
This would require routine mechanical cleaning of the Pins,
the requirement for cleaning may vary depending on the type of Foam You will be using.
.
.
.
Thanks LowQCab, I really appreciate your input.

Sounds like a great idea. Do you have any tips on how this large piece of metal could be heated?

I also think the residue build-up could be a problem. I'll do some more tests to see how it cleans off my piece of test steel.
 

DickCappels

Joined Aug 21, 2008
8,711
If an identical high positive temperature coefficient thermistor is used to heat each finger of your "comb" the fingers will tend toward the same temperature automatically.
 

Picbuster

Joined Dec 2, 2013
1,038
Hello

I'm looking for help with a project I've been wrapping my head around over the past few weeks.

Firstly, I have zero electrical/electronics experience, but I'm only looking for a potential solution to my problem, with which I can take to an electronics engineer, and commission them to manufacture the component for me.

I could take the whole idea to an engineer with the hope they figure out a solution, but I've decided to seek help on this forum too as I'm sure there's many ways that could potentially work.

I require a machine to drill or melt a series of 13 holes in a line (ideally 26 if possible). The holes need to be approximately 3mm in diameter, to be drilled 90mm deep into a foam material, and are spaced on 35mm centres.

I will be manufacturing the framework to hold the system and will create a type of drill press arrangement, which will be attached to the housed components so it can be lowered down into the foam material below.

I've thought about using nichrome or kanthal wire, heated through a circuit system, then lowered into the foam. I've tested a piece of 2.5mm steel heated on a flame, and it melted through the foam perfectly with the hole ending up around 3mm wide. Ideally, this would be the best solution, however the wire would need to be evenly heated throughout the ~100mm total length, and controllable to optimise the best temperature to melt through the foam.

I've thought about using small motors with an attachment to hole a drill bit. I can't imagine this working too well, as the motor housing would have to be 35mm maximum width, in order for the holes to be on 35mm centres and this type of small motor will surely just overheat and not work for long periods of time.

Any ideas on how i'll be able to achieve such a system would be hugely appreciated.

If there's anyone reading this that would be interested in personally working with me on this, please feel free to get in touch and we can discuss pricing.

Thank you!
Hi,
Drilling is possible but:
Speed of the drill depending of the foam density and material. ( heat dissipation )
Drill must be sharpened and shaped for that type of foam. ( shaped: allowing the drill to work the residue up from the hole)

Picbuster
 

MisterBill2

Joined Jan 23, 2018
11,919
If this is for a production system where a whole lot of the drilled pieces will be made, then another option is a laser package to bore the holes and an indexing fixture to advance the foam part 35mm at a step. So the operation would be "step and repeat" for however many holes you need. Laser machining of holes in plastic foam will be very rapid, so the step and repeat will not take long, probably less than 5 milliseconds per hole. Stepping will depend on the resolution and accuracy required.
Production with manual load/unload can be faster if the one fixture can be loaded from either final position and produce the same hole locations moving in either direction.
And the beauty of the laser method is the tools do not need to be resharpened.
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
If this is for a production system where a whole lot of the drilled pieces will be made, then another option is a laser package to bore the holes and an indexing fixture to advance the foam part 35mm at a step. So the operation would be "step and repeat" for however many holes you need. Laser machining of holes in plastic foam will be very rapid, so the step and repeat will not take long, probably less than 5 milliseconds per hole. Stepping will depend on the resolution and accuracy required.
Production with manual load/unload can be faster if the one fixture can be loaded from either final position and produce the same hole locations moving in either direction.
And the beauty of the laser method is the tools do not need to be resharpened.
Thanks for your input there!

I've been machining the material for this particular contract using my CNC router, but as there's ~1600 holes per foam board, it takes almost 2 hours for the CNC to drill each hole. I'm not sure if a laser would be a lot more efficient, as it can still only produce one hole at a time, and regardless of how quick each hole is cut, 1600 holes would probably take at least 45-60 minutes, and I need to get the time down to ~15 minutes.

I appreciate your help!
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
Hi,
Drilling is possible but:
Speed of the drill depending of the foam density and material. ( heat dissipation )
Drill must be sharpened and shaped for that type of foam. ( shaped: allowing the drill to work the residue up from the hole)

Picbuster
Thank you!

Do you have any recommendations for a motor which is small enough? The motor housing cannot be larger than 35mm as the hole centres are 35mm. I will of course need to purchase 13-26 of these and have them all aligned in a row.
 

MisterBill2

Joined Jan 23, 2018
11,919
If you are intending to consider individual motors, consider alternating short and tall. that will allow almost twice the diameter. And laser cutting could be much faster.
 

Sensacell

Joined Jun 19, 2012
3,001
Remember that laser cutting transforms the material directly into vapor- this can be VERY toxic.
If the material contains any chlorine compounds, the fumes will be DEADLY and corrode everything.
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
If you are intending to consider individual motors, consider alternating short and tall. that will allow almost twice the diameter. And laser cutting could be much faster.
Good idea. Do you have any recommendations for the type of motor required for this? Also, can they be wired all together from one power source?
 

MisterBill2

Joined Jan 23, 2018
11,919
Since the requirements for this process are, I guess, high speed and adequate torque, along with adequate bearings, and lifetime, a reasonable choice would be brushless DC motors of the kind that do not use rotor position feedback, since all of them would be fed in parallel from a single inverter.
And now a second option would be to simply bore the holes in two operations. spaced 70mm apart, then step 35mmand bore the second set. That will work if the quantity of holes is an even number, so thirteen motors and one step of 35mm for the second set can be viable. If the requirement is for a rectangular array of holes then a way to accurately step the work in both X and Y directions will be useful.
A very fast robot with a heated tool could do the job , possibly even one hole at a time, if the boring method produced acceptable quality. Those robots are able to produce repeated accuracy within 00.01mm quite rapidly. And the speed while moving to the next position is awesome.
But such an arrangement will require a fair investment in production tooling that is not very flexible or adaptable to other applications.
So far I have not seen any mention about the quality of the surface of the holes , the accuracy of the spacing, or the exact materials. That will make a very large difference in what sort of method is used. Smooth bore holes with an exact diameter are much different from slightly tapered holes with a rough surface.
So a more detailed discussion of the exact requirements will provide a much better insight as to what methods may work best.
AND, it happens that I AM such an engineer, as has designed assorted industrial machines, primarily for the auto industry, both OEMs and their suppliers. Presently I am retired so I no longer have access to all of the resources needed to completely design the machine and provide the needed drawings,but certainly still able to develop the concepts. 20 years ago we could have sent you a detailed proposal and quote for such a machine, along with a reasonable delivery date.
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
Since the requirements for this process are, I guess, high speed and adequate torque, along with adequate bearings, and lifetime, a reasonable choice would be brushless DC motors of the kind that do not use rotor position feedback, since all of them would be fed in parallel from a single inverter.
And now a second option would be to simply bore the holes in two operations. spaced 70mm apart, then step 35mmand bore the second set. That will work if the quantity of holes is an even number, so thirteen motors and one step of 35mm for the second set can be viable. If the requirement is for a rectangular array of holes then a way to accurately step the work in both X and Y directions will be useful.
A very fast robot with a heated tool could do the job , possibly even one hole at a time, if the boring method produced acceptable quality. Those robots are able to produce repeated accuracy within 00.01mm quite rapidly. And the speed while moving to the next position is awesome.
But such an arrangement will require a fair investment in production tooling that is not very flexible or adaptable to other applications.
So far I have not seen any mention about the quality of the surface of the holes , the accuracy of the spacing, or the exact materials. That will make a very large difference in what sort of method is used. Smooth bore holes with an exact diameter are much different from slightly tapered holes with a rough surface.
So a more detailed discussion of the exact requirements will provide a much better insight as to what methods may work best.
AND, it happens that I AM such an engineer, as has designed assorted industrial machines, primarily for the auto industry, both OEMs and their suppliers. Presently I am retired so I no longer have access to all of the resources needed to completely design the machine and provide the needed drawings,but certainly still able to develop the concepts. 20 years ago we could have sent you a detailed proposal and quote for such a machine, along with a reasonable delivery date.
Thank you so much, this is exactly what I'm after.

I currently use my industrial CNC router to bore the holes, one at a time. This takes way too long for the amount of material I have contracts for to machine, hence looking for a manual alternative that an employee would be able to operate.

I'm OK with manufacturing an apparatus to hold the head of motors which will hold the drills in place and the drill press system which will be mounted to a rack and pinion type set-up. At a guess, this apparatus will be the full 8x4 sheet size, and hold the foam material in place so it doesn't move during drilling.

The accuracy really isn't that important, but it has to be roughly 35mm on centres, +/- a couple of mm.

The cleanliness of the finished bore also doesn't matter too much. If some of the swarf remains in the hole, it wouldn't matter.

Are you able to get in touch with me personally so we can work on this?

Thanks again.
 

Tonyr1084

Joined Sep 24, 2015
6,894
The holes need to be approximately 3mm in diameter, to be drilled 90mm deep into a foam material
Is this 90mm deep into a thicker piece of foam or is the foam 90mm and you want to drill all the way through (through hole) holes?

If this is not a through hole situation then consider ordering your foam with the holes in that pattern. Let the foam manufacturer mold the foam around the pins you want. Spacing, depth, size and quantity of holes can be best controlled by molding the foam the way you want it. Otherwise you're dealing with cleanup and waste materials. I've never looked into ordering molded foam before but it might be a cheaper approach than building a machine and hauling off all that wasted foam cut from blanks.
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
Is this 90mm deep into a thicker piece of foam or is the foam 90mm and you want to drill all the way through (through hole) holes?

If this is not a through hole situation then consider ordering your foam with the holes in that pattern. Let the foam manufacturer mold the foam around the pins you want. Spacing, depth, size and quantity of holes can be best controlled by molding the foam the way you want it. Otherwise you're dealing with cleanup and waste materials. I've never looked into ordering molded foam before but it might be a cheaper approach than building a machine and hauling off all that wasted foam cut from blanks.
Thanks for this, however it's a specialist foam for military applications which cannot be produced in any other way than solid sheet form.

Also, having the manufacturer do this would make my interest in the supply of these boards obsolete!
 

MisterBill2

Joined Jan 23, 2018
11,919
OK, this is a lot more useful information relative to what is needed and the required accuracy and product finish. And the application means that the project can either grow or be cancelled. At this point the question arises as to would the production machine be built in-house, or by a machine company?
Also, what part of the world is the TS located in?
 

Tonyr1084

Joined Sep 24, 2015
6,894
Still would like clarification on whether the holes are blind holes (not all the way through) or - um - through holes (all the way through).
 

Thread Starter

MRH91

Joined Feb 20, 2022
13
OK, this is a lot more useful information relative to what is needed and the required accuracy and product finish. And the application means that the project can either grow or be cancelled. At this point the question arises as to would the production machine be built in-house, or by a machine company?
Also, what part of the world is the TS located in?
Great stuff.

Yes, machine to be built in house (I own a fabrication company) plus, the machine doesn't have to be "good looking" but simply utilitarian.

I'm based in Norfolk (U.K).
 
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